Exploring the Characteristics of Individuals Grouped Based on the Multimodal Optimized Treatment for Insomnia Framework Among Individuals Complaining of Insomnia
Article information
Abstract
Objective
This study aimed to explore the feasibility of the Multimodal Optimized Treatment for Insomnia Framework (MOTIF) among people with insomnia symptoms among the general population.
Methods
An online survey among people in the general population complaining of insomnia was conducted anonymously. Participants were categorised into two groups based on 6 hours of time in bed (TIB). Each group was further clustered into two groups based on favourable attitudes toward taking hypnotics. Their psychological states were assessed using the Insomnia Severity Index (ISI), Patient Health Questionnaire-9 (PHQ-9), Dysfunctional Beliefs and Attitudes about Sleep-6 (DBAS-6), Adaptive Cognition and Behaviors about Sleep-6 (ACBS-6), and Depressive Symptoms Inventory-Suicidality Scale (DSI-SS).
Results
There were 600 responses collected, with 548 responses analysed from people whose bedtime was between 9:00 PM and 1:00 AM. In total, 86.1% were categorized as individuals who can sleep without medications, while 13.9% as individuals who cannot. The ISI score was significantly higher among individuals with TIB ≤6 hours. Based on the attitude toward taking hypnotics, the proportions of participants in each category were 46.9%, 39.2%, 7.8%, and 6.0%. The ISI and DSI-SS scores (18.7±5.3 and 2.9±2.6, respectively) were significantly higher among the group who cannot sleep without medications and who had a favourable attitude to taking hypnotics. The proportion of participants taking hypnotics was lowest among the group who cannot sleep without medications and had an unfavourable attitude to taking hypnotics.
Conclusion
Individuals unable to sleep without hypnotics exhibit more severe insomnia symptoms and higher psychological distress.
INTRODUCTION
Physicians frequently encounter insomnia disorder in the clinic [1]. Patients with insomnia show impairment in daytime functioning [2], psychiatric distress such as depression or anxiety, and physical symptoms such as fatigue [3]. Physicians often face difficulties regarding whether they instruct patients with insomnia to continue or stop their sleeping medications or undergo non-pharmacological cognitive behavioural therapy for insomnia (CBT-I) [4]. Unfortunately, many patients with insomnia insist on keeping their hypnotics and clinicians try to convince them to quit. This discrepancy comes from 1) the published practice guideline for the treatment of insomnia which suggests that CBT-I should be administered as first-line therapy prior to prescribing hypnotics and 2) the guidelines suggest that physicians prescribe hypnotics for 4 weeks for usual hypnotics or 3 months for prolonged-release melatonin [5-8]. CBTI is an undoubtedly effective non-pharmacological treatment for insomnia, but many clinicians are not ready to prescribe it owing to its time-consuming nature [9]. Despite clinicians needing to learn CBT-I for the appropriate patients, they sometimes ignore it as a first-line treatment [7]. Further, a limited 4-week hypnotics prescription might be a hurdle for physicians struggling with patients who insist on longer prescriptions to maintain their sleep [5-8].
To minimise this discrepancy, another approach is needed to treat insomnia; therefore, we proposed the Multimodal Op-timized Treatment for Insomnia Framework (MOTIF) [10]. The MOTIF is based on the concept that the first step after diagnosing insomnia disorder is checking whether the patient can or cannot sleep without hypnotics. The basic idea is that clinicians need to conduct CBT-I for patients who can sleep without hypnotics and instruct the patients who cannot sleep without them to take them at least at a lower dosage. However, it is difficult to differentiate between patients who can sleep without medication from those who cannot.
There are some possible clues. First, exploring the risk factors for failing CBT-I may help predict CBT-I failure. Most demographic and medical factors do not consistently relate to CBT-I adherence, although age [11] and higher depressive symptoms [12] may influence it. Stronger motivation, self-efficacy, and perceived relevance of treatment, as well as fewer barriers and greater social support, are associated with better adherence [13]. However, non-adherence to CBT-I does not equate to its ineffectiveness. Previous research has shown that CBT-I is less effective in short sleepers [14]. CBT-I is specifically designed to address insomnia and maladaptive sleep behaviours. However, short sleepers differ in that they do not share the same underlying sleep pathology or dissatisfaction with their sleep as those with insomnia. Consequently, the behavioural and cognitive techniques integral to CBT-I are less relevant and effective for this group.
Second, lower melatonin levels may predict CBT-I failure as the standard guidelines suggest prescribing prolonged-release melatonin to patients aged over 55 years old in whom the melatonin peak level during the night is decreased [15]. However, it is not easy to check melatonin levels in the clinic. Finally, sleep–wake patterns may predict CBT-I failure. Longer duration from waking up to bedtime was associated with short sleep onset latency (SOL) in a previous report [16]. Administering hypnotics 17 hours before waking up was associated with better satisfaction with hypnotics [17,18]. Based on sleep restriction therapy, reduced time in bed (TIB) to increase sleep efficiency is helpful to improve insomnia [19]. Therefore, a patient who cannot fall asleep even with a shorter TIB may be a patient who cannot sleep without hypnotics. In the present study, patients who cannot sleep even after 18 hours of activity (reduced TIB) are defined as those who cannot sleep without hypnotics. Of course, this is a tentative proposal in the situation where evidence-based objective measurement is not available for such patients.
Based on the MOTIF, a patient’s preference for hypnotics is helpful in guiding treatment [10,20]. Among patients who can sleep without hypnotics, CBT-I is the best option. However, if the patient prefers hypnotics, physicians should persuade them not to take hypnotics and encourage CBT-I. Among patients who cannot sleep without medication, hypnotics with optimal pharmacologic treatment at lower dosages might be helpful. However, if a patient does not wish to take hypnotics, their sleep disturbance may remain unresolved. However, this framework has not yet been validated among patients with insomnia. In this study, the feasibility of the MOTIF was theoretically explored among people with insomnia symptoms among the general population.
METHODS
Participants and procedure
An online anonymous survey was conducted among registered general population panels of a professional survey company (EMBRAIN, Seoul, Korea) from June 18–24, 2025. The survey forms included questions on participants’ age, sex, marital status, past psychiatric history, and responses to rating scales. Participants were enrolled if they responded affirmatively to the question, “Have you experienced difficulty falling asleep or maintaining sleep in the past three months?” In addition, to exclude participants with circadian rhythm sleep– wake disorders (CRSWD), eligibility required affirmative responses to the question, “Do you go to bed between 9:00 PM and 1:00 AM every day?” Participants were excluded if they responded affirmatively to the question, “Are you working a shift?” Finally, participants proceeded with the survey after affirming their agreement to the provided questions.
The estimated sample size was 600 by allocating 50 samples per 12 cells (sex×6 age groups) based on the central limit theorem. The company sent 7,558 emails to 1.8 million registered panels, 1,882 accessed the survey, and 640 completed it. The company excluded the fastest 5% of respondents in each quota based on response time, ensuring only valid samples were retained. Additionally, responses were excluded if the average time spent between questions exceeded three times the overall average. Finally, the company delivered the 600 de-identified responses to the researchers. The study protocol was approved by the Institutional Review Board of the Asan Medical Center (approval number: 2025-0607).
Measures
Defining an individual who can or cannot sleep without hypnotics
There is currently no method to determine objectively whether an individual can or cannot sleep without hypnotics. Neither polysomnography, electroencephalography, nor brain imaging can provide this information. Thus, these states were defined in this study using participants’ sleep indices. Age-adjusted self-reported sleep duration was reported as 7.40 hours in 1985, 7.29 hours in 1990, 7.18 hours in 2004, and 7.18 hours in 2012 in the United States. In the same study, the age-adjusted percentage of adults sleeping ≤6 hours was 22.3% in 1985, 24.4% in 1990, 28.6% in 2004, and 29.2% in 2012 [21]. In addition, short sleepers were defined as those reporting <6 hours of sleep [22], and the effect of CBT-I for those with insomnia with objective short sleep duration was reportedly blunt [23,24]. Therefore, an individual unable to sleep without hypnotics is defined as someone with insomnia, even if their TIB is 6 hours or less. In this study, to compare definitions, these individuals were defined as someone with insomnia even if their TIB is 7 hours or less.
Sleep indices and discrepancy between desired time in bed and desired total sleep time
Participant variables such as bedtime, sleep onset time, final wake time, and wake-up time were assessed using questions of “What is your usual bedtime?,” “What is your usual time to fall asleep?,” “What time do you finally awake?,” and “What is your usual time to finally get out of bed in the morning?” Using the responses, duration variables such as SOL or TIB were calculated. If participants were taking hypnotics, they were asked when specifically they take hypnotics [16-18].
The discrepancy between desired time in bed and desired total sleep time (DBST index) is calculated as the difference between the patient’s desired total sleep time (dTST), estimated based on the response to the question, “For how many hours do you wish to sleep a day?” and the desired TIB (dTIB) determined by responding to the question, “From what time to what time do you wish to sleep?” The DBST index is calculated as [dTIB]–[dTST] [25-27].
Questions on insomnia symptoms and taking hypnotics
Participants were asked if they experience insomnia and, if yes, about their symptoms (initiating problem, maintenance problem, or both). In addition, participants were asked about whether they were taking hypnotics. If they did, they were asked about the time they took hypnotics and their satisfaction with the hypnotics they were using, employing the question, “How satisfied are you with your hypnotics?” Participants responded with “very satisfied,” “satisfied,” “unsatisfied,” or “very unsatisfied.” In this study, satisfaction with hypnotics was defined as answers of “very satisfied” or “satisfied.”
Favourable attitudes toward taking hypnotics
Participants’ attitudes toward using hypnotics were assessed by asking, “What is your opinion on taking hypnotics for your own use?” Responses included options such as “I absolutely never want to take hypnotics,” “I do not want to take hypnotics,” “I think it is okay for me to take hypnotics,” or “I think I can sleep adequately just with hypnotics.” In this study, a favourable attitude toward using hypnotics was defined as an answer of “I think it is okay for me to take hypnotics” or “I think I can sleep adequately just with hypnotics,” and an unfavourable attitude as an answer of “I absolutely never want to take hypnotics” or “I do not want to take hypnotics.”
Insomnia Severity Index
The Insomnia Severity Index (ISI) is a self-report scale developed by Bastien et al. [28] to assess an individual’s insomnia severity. It contains seven items rated on a 5-point Likert scale. A total score can range from 0–28, with 0–7 indicating no clinically significant insomnia, 8–14 indicating subthreshold insomnia, 15–21 indicating moderate clinical insomnia, and 22–28 indicating severe clinical insomnia. The Korean version was validated with a Cronbach’s alpha of 0.828 [29].
Patient Health Questionnaire-9
The Patient Health Questionnaire-9 (PHQ-9) is a self-report rating scale developed by Kroenke et al. [30] to assess an individual’s severity of depressive symptoms. It contains nine items rated on a 4-point Likert scale from 0 (“not at all”) to 3 (“nearly every day”), with a maximum total score of 27. The total score reflects the severity of depression: 0–4 as none or minimal, 5–9 as mild, 10–14 as moderate, 15–19 as moderately severe, and 20–27 as severe. The Korean version was validated with a Cronbach’s alpha of 0.892 [31].
Dysfunctional Beliefs and Attitudes about Sleep-6
The Dysfunctional Beliefs and Attitudes about Sleep-6 (DBAS-6) [32] is a self-report scale which was shortened using machine-learning approaches from the DBAS-16 scale [33]. The DBAS-6 contains six items rated on an 11-point Likert scale between 0 (“strongly disagree”) and 10 (“strongly agree”). The final score is an average of all six items, and a higher average score reflects a higher level of dysfunctional beliefs about sleep. The Korean version was used in this study, with a Cronbach’s alpha of 0.767.
Adaptive Cognition and Behaviors about Sleep-6
The Adaptive Cognition and Behaviors about Sleep-6 (ACBS-6) is a self-report rating scale developed by Chung et al. [34] to assess an individual’s sleep-related adaptive cognition and behaviours. It contains six items clustered into two factors such as adaptive sleep-related cognition and adaptive sleeprelated behaviours. Participants rate their agreement to items using an 11-point Likert scale between 0 (“strongly disagree”) and 10 (“strongly agree”). The final score is an average of all six items, and higher scores reflect a higher level of adaptive sleeprelated cognition and behaviours. The original Korean version was used in this study, with a Cronbach’s alpha of 0.740.
Depressive Symptoms Inventory-Suicidality Scale
The Depressive Symptoms Inventory-Suicidality Scale (DSISS) is a self-report rating scale developed to assess suicidality among individuals [35]. It consists of four items that specifically measure suicidal thoughts and behaviours. Participants are asked to rate the frequency or intensity of each symptom over the past two weeks, typically using a Likert-type scale (e.g., 0–3 points per item). The total score is calculated by summing all item scores, and a cut-off score of 3 or above is generally considered indicative of clinically significant suicide risk. The Korean version was used in this study [36], with a Cronbach’s alpha of 0.935.
Statistical analysis
Continuous variables were presented as mean±standard deviation, and categorical variables as number and percentage. First, participants were categorised into two groups depending on who can and cannot sleep without hypnotics based on a TIB of 6 hours. Between-group comparisons were performed using Student’s t-test for continuous variables and the chi-squared test for categorical variables. Second, each group was divided into two subgroups based on having a favour-able attitude to taking hypnotics or not. Comparisons among all four groups were performed with analysis of variance for continuous variables and the chi-squared test for categorical variables. Post hoc analysis was performed using the Scheffe test. Third, Pearson’s correlation coefficients were examined among clinical variables to explore which variables were associated with ISI scores. Finally, linear regression analysis with the “enter” method was used to explore variables which contribute to insomnia severity. In this model, the MOTIF group, based on 6 hours of TIB, was added as a dummy variable. JASP version 0.14.1.0 software (JASP team) was used for statistical analysis.
RESULTS
There were 600 responses collected from participants who responded “yes” to the question of “Do you go to bed between 9:00 PM and 1:00 AM every day?” However, some participants recorded their bedtime as before 9:00 PM or after 1:00 AM. As a result, 52 participants were excluded, leaving a total of 548 responses from participants for final analysis.
Participants were categorised as those who cannot sleep without hypnotics (n=76, 13.9%) and those who can (n=472, 86.1%) based on 6 hours of TIB (Table 1). There were no significant differences in age, sex, marital status, and past psychiatric history between these groups. In terms of current insomnia, there were no significant differences in insomnia type or proportion of taking hypnotics. Bedtime and sleep onset time were later, final awake time and get out of bed time were significantly earlier, and SOL and TIB were shorter among individuals with a TIB ≤6 hours compared to those with a TIB >6 hours. Among rating scales, only the ISI score was significantly higher among individuals with TIB ≤6 hours. Based on the attitude to taking hypnotics, the proportion of participants in each category (TIB >6 hours, favourable toward hypnotics [Group A]: n=257, 46.9%; TIB >6 hours, unfavourable toward hypnotics [Group B]: n=215, 39.2%; TIB ≤6 hours, favourable toward hypnotics [Group C]: n=43, 7.8%; TIB ≤6 hours, unfavourable toward hypnotics [Group D]: n=33, 6.0%) are described in Table 2 and Figure 1. The ISI score (18.7±5.3) and DSI-SS score (2.9±2.6) were significantly higher in Group C compared to other groups (p<0.01). The proportion of participants who are taking hypnotics was significantly higher among Groups A (24.9%) and C (23.3%) compared to Groups B (16.3%) and D (6.1%). Further, the proportion of participants who are taking hypnotics was lowest among Group D (6.1%).
Baseline demographic and clinical characteristics of the participants categorised based on TIB ≤6 hours (N=548)
Baseline demographic and clinical characteristics of the participants categorised based on TIB ≤6 hours and attitude toward taking hypnotics (N=548)
Proportion of participants based on the MOTIF based on categorizing them into being able or unable to sleep without hypnotics defined as TIB ≤6 hours. MOTIF, Multimodal Optimized Treatment for Insomnia Framework; TIB, time in bed; ISI, Insomnia Severity Index.
In addition, based on 7 hours of TIB, participants were categorized into those who can and cannot sleep without hypnotics (Table 3). More individuals with TIB ≤7 hours were male compared to those with TIB >7 hours (p=0.006). The proportion of participants with past psychiatric history was significantly higher among individuals with TIB >7 hours (p=0.029). There was no significant difference in the proportion of participants taking hypnotics between groups. The results of sleep indices were similar to the results from when participants were categorised based on 6 hours of TIB. Among rating scales, only the ISI score was significantly higher among individuals with TIB ≤7 hours (p=0.016). Based on the attitude to taking hypnotics, the proportions of participants in each cat-egory (TIB >7 hours, favourable toward hypnotics [Group A]: n=203, 37.0%; TIB >7 hours, unfavourable toward hypnotics [Group B]: n=161, 29.4%; TIB ≤7 hours, favourable toward hypnotics [Group C]: n=97, 17.7%; TIB ≤7 hours, unfavourable toward hypnotics [Group D]: n=87, 15.9%) are described in Table 4 and Figure 2. The ISI score was significantly higher among Group C compared to Group B. The proportion of participants who are taking hypnotics was significantly higher in Group A compared to Groups B, C, and D. Further, the proportion of participants who are taking hypnotics was lowest in Group D (10.3%).
Baseline demographic and clinical characteristics of the participants categorised based on TIB ≤7 hours (N=548)
Baseline demographic and clinical characteristics of the participants categorised based on TIB ≤7 hours and attitude toward taking hypnotics (N=548)
Proportion of participants based on the MOTIF based on categorizing them into being able or unable to sleep without hypnotics defined as TIB ≤7 hours. MOTIF, Multimodal Optimized Treatment for Insomnia Framework; TIB, time in bed; ISI, Insomnia Severity Index.
Table 5 showed that ISI was significantly correlated with PHQ-9 (r=0.61, p<0.01), DBAS-6 (r=0.47, p<0.01), ACBS-6 (r=-0.13, p<0.01), DSI-SS (r=0.32, p<0.01), and the DBST index (r=0.10, p<0.05). Results of partial correlation coefficients showed similar results. In terms of sleep indices (Table 6), late bedtime was significantly correlated with short SOL and TIB (both p<0.01) and the results of partial correlation showed similar results. The ISI score was significantly correlated with late sleep onset time (r=0.21, p<0.01), early final wake time (r=-0.11, p<0.05), and long SOL (r=0.19, p<0.01). Partial correlation showed no association between ISI scores and final wake time.
Pearson correlation coefficients among variables (N=548)
Pearson correlation coefficients among variables (N=548)
Linear regression analysis showed that the ISI was associated with age (β=-0.08, p=0.018), PHQ-9 (β=0.47, p<0.001), ACBS-6 (β=-0.14, p<0.001), DBAS-6 (β=0.25, p<0.001), final wake time (β=-0.15, p<0.001), and MOTIF Group C (β=0.30, p=0.026 (Table 7).
Linear regression analysis of variables contributing to insomnia severity
DISCUSSION
The MOTIF serves as a framework to enhance procedures for prescribing hypnotics. However, it has not been validated yet. This study is the first to investigate the feasibility of the MOTIF framework, a structured approach aimed at improving insomnia treatment. In this study, participants with shorter TIB, whether ≤6 or ≤7 hours, showed significantly later bedtimes, earlier wake times, and higher insomnia severity compared to those with longer TIB. Categorisation by both TIB and attitudes toward hypnotics revealed that groups with stronger dependence on hypnotics (Groups A and C) had higher proportions of current hypnotic use and, for Group C, notably higher ISI and DSI-SS scores.
In this study, an individual who cannot sleep without hypnotics was defined as someone having insomnia even with a TIB ≤6 hours, and the ISI score was higher in individuals unable to sleep without hypnotics compared to those who can. In the concept of sleep restriction therapy in CBT-I, sleep efficiency may be increased when TIB is reduced [19]. However, the short TIB group in the present study showed more severe insomnia symptoms. This may be because individuals who cannot sleep without hypnotics have more severe insomnia. Several studies have identified that patients with insomnia and short sleep duration represent a more severe and biologically distinct phenotype of insomnia [37,38]. Specifically, research shows that insomnia with objective short sleep duration is associated with greater activation of the stress system, higher risks for cardiometabolic and neurocognitive morbidity, and an unremitting course of illness. This group is considered the most biologically severe form of insomnia. This result was consistent in that MOTIF Group C showed the highest ISI and DSI-SS scores compared to other groups. Individuals in MOTIF Group D have an unfavourable attitude to taking hypnotics, and the low proportion of taking hypnotics was expected. However, contrary to expectations, the insomnia severity of MOTIF Group D was lower compared to Group C. The MOTIF considers that insomnia symptoms may be per-sistent among individuals who are unable to sleep without hypnotics and have an unfavourable attitude to taking hypnotics, and they might be considered to have insufficient sleep syndrome [39]. Furthermore, short sleepers [22] can also be categorised in this group. These results need to be explored further.
In this study, the MOTIF group based on 7 hous of TIB showed similar results with the MOTIF group based on 6 hours of TIB. The purpose of this study was to identify individuals who cannot sleep without hypnotics. Therefore, it is preferable to minimise the proportion of individuals classified as needing hypnotics. When using a TIB criterion of 6 hours, the proportion of individuals who cannot sleep without hypnotics is 13.9%, whereas using a TIB criterion of 7 hours increases this proportion to 33.6%. Therefore, cases in which individuals are unable to sleep despite having a TIB of 6 hours or less could be considered as those who cannot sleep without hypnotics.
The linear regression analysis revealed several significant factors associated with insomnia severity as measured by the ISI. Younger age, higher levels of depressive symptoms (PHQ-9), and more dysfunctional beliefs about sleep (DBAS-6) were all linked to greater insomnia severity. In contrast, higher levels of adaptive sleep-related cognition (ACBS-6) and later final wake times were associated with lower ISI scores. Additionally, individuals in MOTIF Group C were associated with higher ISI scores even in the linear regression analysis, suggesting that this subgroup may represent individuals with particularly severe insomnia. Identifying such high-risk groups can help clinicians tailor interventions more effectively and improve treatment outcomes for patients struggling with chronic insomnia.
There are certain limitations in this study. First, individuals who experienced difficulty falling asleep or maintaining sleep in the past three months were enrolled via an online survey. Enrolling individuals with insomnia through online surveys is uncommon [40], although numerous online surveys have been conducted for validation studies among the general population [41,42]. However, participants were asked if they had experienced either initiation or maintenance insomnia within the past 3 months, which may represent a stringent criterion for enrolment. It is reasonable to investigate a clinical sample of patients with insomnia, but this may introduce potential clinician bias while categorising patients into those who can or cannot sleep without hypnotics. Second, the definition of “inability to sleep without hypnotics” in this study was set as 6 hours of TIB, which is not a common definition. Clinically, it remains challenging to objectively determine whether an individual can or cannot sleep without hypnotics. Nevertheless, there are undoubtedly patients who remain unable to sleep without hypnotics even after undergoing CBT-I. Thus, the inability to sleep without hypnotics was defined as 6 hours of TIB based on the concept of sleep restriction therapy in CBTI. If an individual cannot sleep even after reducing their TIB to 6 hours, they may require hypnotics. However, this is merely an empirical observation and lacks supporting evidence. A 7-hour total sleep time was also applied in this study to compare proportions, alongside 6 hours of sleep time, as it represents an average sleep duration in the general population. While 6 hours of TIB is not supported by prior evidence, 7 hours serves as a comparative benchmark to evaluate proportions across different TIB thresholds. Further research is required to establish a standardised definition of the inability to sleep without hypnotics. Third, psychological acceptance of hypnotics was defined as a participant’s response to “Do you prefer to take sleeping pills?” While this may be practical, a more comprehensive rating scale could enhance the assessment. Further research is required to develop comprehensive rating scales for assessing acceptance of hypnotics and their associated disability. Fourth, the use of anonymous surveys and subjective rating scales may introduce bias in such an online survey. The results should be interpreted with caution. Fifth, the sample size of group C and D is small and it might influence the statistical analysis results. It needs to be interpreted with caution. Last, we could not exclude the possible sleep disorder such as obstructive sleep apnea or restless legs syndrome which can influence the sleep disturbance. In addition, we could not exclude underlying medical condition such as pain [43] or physical disability which influence participant’s sleep due to this anonymous online survey. Furthermore, we included participants whose habitual bedtime as 9:00 PM to 1:00 AM to exclude the possible CRSWD in this survey. However, it is not enough to exclude the CRSWD exactly via online survey.
In conclusion, this study is the first to explore the feasibility of the MOTIF, a structured approach for categorizing patients with insomnia who can or cannot sleep without hypnotics and attitudes toward hypnotic use. The findings demonstrate that individuals with short TIB (≤6 hours), particularly those unable to sleep without hypnotics. The results also highlight that using a 6-hours TIB threshold more specifically identifies individuals with the most severe insomnia and the greatest dependence on hypnotics, compared to a 7-hours threshold. The MOTIF framework may assist clinicians in identifying a subgroup of patients with insomnia who are both highly symptomatic and dependent on hypnotics, allowing for more targeted interventions. Defining “inability to sleep without hypnotics” as persistent insomnia despite a TIB of 6 hours or less could serve as a practical clinical marker for severe and treatment-resistant insomnia.
Notes
Availability of Data and Material
The datasets generated or analyzed during the study are available from the corresponding author on reasonable request.
Conflicts of Interest
Seockhoon Chung, a contributing editor of the Psychiatry Investigation, was not involved in the editorial evaluation or decision to publish this article.
Funding Statement
This research was supported by the National IT Industry Promotion Agency (NIPA) of the Republic of Korea (H1002-24-1002).
Acknowledgments
None